Question

$1$ mole of an ideal gas at ${25}^o$C is subjected to expand reversibly and adiabatically to ten times of its initial volume. Calculate the change in entropy during expansion (in $J{k}^{-1}$ $m{o}^{-1}$).

• A. $19.15$
• B. $-19.15$
• C. $4.7$
• D. Zero

Answer 1

The correct option is A $19.15$

Let us consider the problem.

Hence the change in entropy

$\Delta S=\frac{q}{T}=\frac{-\left(-2.203nRT\log \frac{V_2}{V_1}\right)}{T}$

$\left(Sinceq=-w=-2.203nRT\log \frac{V_2}{V_1}\right)$

$=2.203nR\log \frac{V_2}{V_1}$

Implies that

$=2.203\times 1\times 8.314\times \log \frac{10}{1}$

Implies that

$=19.15J/K/mol$